hi, I'm new to keeping piranhas i just had mine 4 days ago. i have a 50"L x 24" W x 20" H gallon tank with 5 2.5 to 3 inches piranhas. im just worried of losing one of them because i noticed that one of them had his tailfin nipped at the top portion today after i arrived from work. when i first got them i gave XO dried shrimp a chinese brand fish food on the day i bought them then gave them fish fillet up to now. when i got them i i also bought some neon tetras so they can have some exercise chasing them and to redirect their aggression towards each other, but yesterday the neon tetras were all gone. so thats the current scenario, i know based on the research i had and reading the forums that its sometimes inevitable not to lose some piranhas because its their nature but if i can do something to prevent or minimize the lost ill do all i can thats why i need your advice. thanks